The father of former All Black Keith Robinson has been trespassed from a Te Aroha business after allegedly making a gun gesture at staff on Christmas Eve.

The altercation appears linked to an earlier incident in which Keith Robinson assaulted an older man outside the Palace Hotel in Te Aroha on December 9.

Robinson, 36, has admitted a charge of injuring with intent to injure for the attack, which onlookers said left a man unconscious and bleeding on the road.

In the second incident, Robinson's father, Jock Robinson, went to a man's workplace and confronted him for reporting the assault to police.

One witness told the Waikato Times Jock Robinson appeared "quite angry and annoyed" and demanded to know why the man had laid an assault complaint against his son.

"Jock was quite confrontational from the start; he wasn't overly loud but his tone was confrontational," the witness said.

"He was saying, ‘Why the f... did you call the police?'."

Mr Robinson was eventually asked to leave the store by staff and allegedly responded by doing a threatening gun gesture. "As he's leaving, he turned back and put his fingers to his head in the form of a gun and pulled the trigger," the witness said.

"He [Mr Robinson] didn't say anything when he did this, he just pointed to his temple, formed a gun with his fingers, and made a shooting signal."

Te Aroha police confirmed a complaint had been laid against Mr Robinson by two men but could not say whether any charges would follow.

Mr Robinson was subsequently trespassed from the Ema St business.

The Times was unable to contact Mr Robinson for comment.

Meanwhile, Keith Robinson is due to reappear in the Hamilton District Court this month over the assault.

The former All Black and close to 50 others were at an event hosted by the Palace Hotel on the day of the assault.

Robinson made his All Black debut in 2002 against England at age 25 and went on to play 12 tests.